Padma Vasudevan

Biosorption of nickel(II) ions on Baker's yeast

Abstract The biosorption of nickel(II) ions by deactivated protonated yeast was investigated with respect to the initial pH and initial metal ion concentration. The kinetics of sorption was also followed based on the amounts of metal sorbed at various time intervals for different yeast doses. The equilibrium data could be fitted by the Langmuir isotherm model. The adsorption capacity was pH dependent with a maximum value of 11.4 mg/g at a pH of 6.75. The nickel(II) ion uptake was pseudo-second order with respect to metal concentration and was yeast dose dependent. The rate constant, the equilibrium sorption capacity and the initial sorption rate are reported.

Kinetics of biosorption of cadmium on Baker’s yeast

In the present study the kinetics of biosorption of cadmium(II) ions by deactivated protonated yeast converted to sodium form was investigated for different initial concentrations of the metal ion (10-100 ppm) and different sorbent dosages (0.1-2.0 g) at a pH of 6.5. The adsorption process occurred in four distinct steps and the rates for these steps decreased sequentially. The rate of cadmium uptake in each case was pseudo-second-order with respect to metal ion concentration. The amount sorbed at equilibrium was found to be directly proportional to the initial metal ion concentration divided by the sorbent mass.

Biosorption of monovalent and divalent ions on baker's yeast.

Biosorption of monovalent ions Na+ and K+, by deactivated protonated yeast (Saccharomyces cerevisiae) at controlled pH, was compared with biosorption of divalent ions Ca2+ and Mg2+ to help to understand the underlying bindingmechanisms. The adsorption for monovalent ions was accompanied by H+ release. Divalent ions were sorbed by proton displacement, and also an additional mode not accompanied by release of H+. The sorption uptake of both monovalent and divalent metal ions increased with pH in the range 3-7 peaking at 6.75. Equilibrium sorption isotherms at pH = 6.75 showed that the totalmaximum biosorptive capacity for metal ions decreased in the following order: Ca > Mg > Na > or = K.

Larvicidal and repellent actions of Dalbergia sissoo Roxb. (F. Leguminosae) oil against mosquitoes

Abstract Studies were carried out to evaluate the larvicidal, growth inhibitor and repellent actions of D. sissoo oil against Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus under laboratory conditions. Pure oil was applied at 0.4–5 ml/m2 on a water surface. This showed that larvicidal activity was directly proportional to dosages. One hundred percent mortality of Cx. quinquefasciatus immatures was observed within 24 h at 4 ml/m2, followed by Ae. aegypti (90%) and An. stephensi (60%), and pupation was totally inhibited. Adults which emerged from exposure to a sublethal dosage (2 ml/m2) either did not lay eggs (Ae. aegypti) or hatch (Cx. quinquefasciatus and An. stephensi). The oil also showed strong repellent action when 1 ml oil was applied on exposed parts of human volunteers. They were protected from mosquito bites for 8–11 h. The protection (91.6±2%) obtained with sissoo oil was comparable to that with commercial Mylol oil (93.8±1.2%) consisting of di-butyl and dimethyl phthalates.

Cultivation of Pleurotus sajor-caju on different wastes

Abstract Cultivation of Pleurotus sajor-caju, an edible mushroom, was tested on leaves of Morus alba and Ricinus communis and also on stems (chopped as well as on wood logs). The mushrooms were analysed for their protein content, carbohydrate, ash percentage, fat content, crude fibre and mineral contents. The yield obtained from M. alba was comparable with the yield obtained from paddy straw. The recycling of organic waste or waste biomass through mushroom cultivation is represented diagramatically and the economics of this cultivation have been worked out.

p-Amino salicylic acid — oxidized cellulose system: a model for long term drug delivery

The mobilization of p-amino salicylic acid (PASA) on periodic oxidized cellulose (O.C) as a biocompatible carrier was investigated. The immobilization of the PASA is based on Schiffs base formation between the amino group of PASA and the aldehyde group of O.C. The in vivo and in vitro release of p-amino salicylic acid was studied. Such a system may be useful for the sustained delivery of the drugs in the body, since O.C. itself is a biosoluble carrier.

Estimating the above ground biomass of Ipomoea fistulosa by regression methods

Abstract This paper describes a method for the estimation of above ground biomass of Ipomoea fistulosa through linear regression based on three variables; observed weight, W0, as dependent variable and basal diameter of stem, D, and height of plant, H, as independent variables. Linear equations for estimated biomass weights, W : W 1 = bD + C and W 2 = aH + bD + C gave better results than non-linear equations W 3 = B . D2H + C and W 4 = C.D. b H a . Regression showed a linear relation between weight and diameter while height appeared to be a redundant factor for estimation of aerial biomass.

Increasing biomass yields of hardy weeds through coppicing—Studies on Ipomoea fistulosa and Adhatoda vasica with reference to wasteland utilization

Abstract Growing dependence on standing plantations for fuel is creating many ecological imbalances. Wasteland utilization by growing hardy weeds with coppicing properties and ability to regenerate quickly can fulfil the needs of fuel and fertilizer along with soil conservation of the exposed lands. Fast-growing shrubby weeds can be coppiced regularly and their biomass yields can be optimized by identifying the time period (Growth Period) after which coppicing should be done. With the establishment of root system and a certain growth of the shoot system, the plant becomes ready for regeneration after cutting. Field level studies of physical composition of Ipomoea fistulosa and Adhatoda vasica indicated growth periods in terms of plant height after which the plants produced more secondary growth. A primary growth level in terms of height of main stem has been worked out, after which the first coppice could be done.

Trigeneration using biomass energy for sustainable development

Purpose: The paper aims to design and prove the concept of micro-industry using trigeneration fuelled by biomass, for sustainable development in rural NW India. Design/methodology/approach: This is being tested at village Malunga, near Jodhpur in Rajasthan. The system components comprise burning of waste biomass for steam generation and its use for power generation, cooling system for fruit ripening and the use of steam for producing distilled water. Site was selected taking into account the local economic and social needs, biomass resources available from agricultural activities, and the presence of a NGO which is competent to facilitate running of the enterprise. The trigeneration system was designed to integrate off-the-shelf equipment for power generation using boilers of approximate total capacity 1 tonne of fuel per hour, and a back-pressure steam turbo-generator (200 kW). Cooling is provided by a vapour absorption machine (VAM). Findings: The financial analysis indicates a payback time of less than two years. Nevertheless, this is sensitive to market fluctuations and availabilities of raw materials. Originality/value: Although comparable trigeneration systems already exist in large food processing industries and in space heating and cooling applications, they have not previously been used for rural micro-industry. The small-scale (1-2 m3/h output) multiple effect distillation (3 effect plus condenser) unit has not previously been deployed at field level.

Oil bearing seasonal crops in India: energy and phytoremediation potential

Purpose: A variety of biomass plantations are being raised for energy production. This case study is on energy production potential of seasonal oil bearing crops in India. These crops have the advantage of producing oil (liquid fuel) as well as biomass as agro residue (solid fuel). The purpose of the study is to estimate total energy yields of oil bearing crops and compare with other types of energy plantations. Also oil bearing crops bioaccumulate metals and thus phytoremediate soil. This provides scope for waste water irrigation. Design/methodology/approach: Relevant published papers on energy production by raising oil bearing crops have been analyzed. The effect of waste water irrigation and agronomic practices on increasing productivity is given special attention. Findings: It is shown that the seasonal oil bearing crops such as castor have a high potential to generate energy and this is comparable to energy produced by many perennial grasses. The energy yields of castor under irrigated condition was 196×103 MJ/ha and this is comparable to the reed canary grass which yields 195×103 MJ/ha. Some of the oil bearing crops are also super accumulators of certain toxic metals. Research limitations/implications: In this study, only all the accessible papers on the topic could be analyzed. Practical implications: This case study indicates that raising oil bearing crops such as castor using waste water has many advantages which include high energy yields, utilization of waste water for productive purpose and phytoremediation of soil. Originality/value: The comparison made between various types of energy crops for their energy generation is an original contribution. Findings of economic and environmental benefits by waste water irrigation are also of value.